516487 divided by 81 
The aim is to understand the frequency of 81 in 516487.

On to step 1:
5 divided by 81 is 0 with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 81

Advancing to step 2:
When dividing 51 by 81, we get 0 with a remainder of 51.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 51 and we're left with 51.
Append the next digit (6) from the dividend to 51 and continue with: 516 / 81

Moving on to step 3:
If we divide 516 by 81, we get 6 and a remainder of 30.
Put 6 as the next digit of the answer. 
Result so far: 6.0
If we take 486 away from 516, we end up with 30.
Grab the next digit (4) from the dividend, add it to 30, then carry on: 304 / 81

Advancing to step 4:
304 divided by 81 is 3 with a remainder of 61.
The number 3 becomes the next digit in our result. 
Result so far: 63.0
Subtracting 243 from 304 leaves us with 61.
Take the next digit (8) from the dividend and append it to 61, then repeat: 618 / 81

Going ahead to step 5:
81 goes into 618 7 times with a remainder of 51.
Put 7 as the next digit of the answer. 
Result so far: 637.0
Subtract 567 from 618 to get 51.
Grab the next digit (7) from the dividend, add it to 51, then carry on: 517 / 81

Step 6:
81 goes into 517 6 times with a remainder of 31.
The number 6 becomes the next digit in our result. 
Result so far: 6376.0
Subtract 486 from 517 to get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Moving on to step 7:
The number 81 fits into 310 3 times, leaving a remainder of 67.
Write down 3 as next digit of the result. 
Result so far: 6376.3
The remainder is 67 after subtracting 243 from 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

On to step 8:
81 can be fit into 670 8 times, resulting in a remainder of 22.
The next digit of our result is 8. 
Result so far: 6376.38
If we subtract 648 from 670, we get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Let's proceed to step 9:
If we divide 220 by 81, we get 2 and a remainder of 58.
The number 2 becomes the next digit in our result. 
Result so far: 6376.382
Subtract 162 from 220 to get 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Moving on to step 10:
The number 81 fits into 580 7 times, leaving a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 6376.3827
If we take 567 away from 580, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 11:
81 can be fit into 130 1 times, resulting in a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 6376.38271
Subtract 81 from 130 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Advancing to step 12:
81 goes into 490 6 times with a remainder of 4.
The next digit of our result is 6. 
Result so far: 6376.382716
Deduct 486 from 490 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 13:
40 divided by 81 is 0 with a remainder of 40.
Use 0 as the next digit of our solution. 
Result so far: 6376.382716
The remainder is 40 after subtracting 0 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 14:
400 divided by 81 is 4 with a remainder of 76.
Write down 4 as next digit of the result. 
Result so far: 6376.38271604
Subtracting 324 from 400 leaves us with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

After the division, we end up with 6376.38271604 and a remainder of 7.6e-08.